Casella CEL Nomad portable weather station - Manual (Page 60)

one-way communication, with data being transmitted continuously to the PC, as
described in Chapter 4. The default rate is to download at 20 second intervals.
Nomad systems fitted with a Low Power Radio link are delivered
pre-configured ready for use.
The low power radio operates at a nominal frequency 458 MHz, on
eight channels that can be selected by the user. Channel selection is
accomplished by setting a 3 X 3 pin header on the Transmitter Module as
detailed in Table 4.
Table 4: Selection of low power radio channels
CS0 CS1 CS2 Channel Frequency (MHz)
1 - 2 1 - 2 1 - 2 7 458.6000
1 - 2 1 - 2 2 - 3 6 458.5750
1 - 2 2 - 3 1 - 2 5 458.5625
1 - 2 2 - 3 2 - 3 4 458.5500
2 - 3 1 - 2 1 - 2 3 458.5375
2 - 3 1 - 2 2 - 3 2 458.5250
2 - 3 2 - 3 1 - 2 1 458.5125
2 - 3 2 - 3 2 - 3 0 458.5000
These frequencies are those programmed for UK standard MPT1329
license exempt equipment.
8.4.1 Low Power Radio Transmitter Specification
Frequency range 458.5 to 458.6 MHz (8 channels)
Frequency stability ±2 ppm
Number of RF channels RS232 or 1 of 8 parallel select
RF output power
into 50
Ω
100 mW
Adjacent channel power <200 mW (-37 dBm)
TX switching time
<60 ms
Modulation input
analogue 200 mV to 5 V p-p AC coupled
digital +3 to 12 V square wave DC coupled
Frequency response 9 Hz to 3 kHz at -3 dB
Deviation with 12.5 kHz
channel spacing ±1.5 kHz nominal (±2.5 kHz max)
Channel switching delay <50 mS across switching bandwidth
Channel spacing
12.5 kHz/20 kHz/25kHz available
Modulation type FID/F2D/F3D
Spurious emissions
conducted & radiated In accordance with ETS/CEPT specifications
Supply voltage 6 - 15 V DC -ve earth
Supply current at 7.2V <100 mA for 100 mW output
Interface connections 2- and 10-pin 0.1" header
RF connection 3-pin 0.1" header
Operating temperature -20°C to +55°C
Storage temperature -30°C to +70°C
Size overall 60 x 39 x 15 mm
2.36 x 1.53 x 0.59 inches
Weight 30 gm
Type approval Designed to meet ETS 300/220 and MPT 1329
Communication
Page 60 of 68
NOMAD Portable Weather Station
Users Handbook